But the breaker did trip after all

Status
Not open for further replies.

mbrooke

Batteries Included
Location
United States
Occupation
Technician
Just because a short circuit does not trip a breaker on its instantaneous magnetic trip curve does not mean it will never shut off a second latter on its thermal trip curve, and this video actually proves that. The guy says the fault never draws more then 20amps, but that is a lie because the regular breaker tripped a few round after. Being how quick it did trip especially with a second between cuts shows that the fault current is well over 20amps, more like 100amps. Also notice the 3 wire extension cord used in the test. A GFCI break would have done the EXACT same thing since the EGC gets involved. The explanation of sparks dissipating electrons into space is also incorrect. Starting 10:20 here, a regular breaker vs an AFCI receptacle:



https://www.youtube.com/watch?v=dENKTpgZtEk
 

mbrooke

Batteries Included
Location
United States
Occupation
Technician
Then the answer is 42.:cool:



:?:?


Yes the RMS current is lower then that of a dead bolted fault, but still high enough to open the OCPD within a few seconds. The way AFCIs are advertised is that if a short circuit takes place with sputtering (as most sputter) that a regular breaker will never trip. This is simply untrue.
 

jumper

Senior Member
:?:?


Yes the RMS current is lower then that of a dead bolted fault, but still high enough to open the OCPD within a few seconds. The way AFCIs are advertised is that if a short circuit takes place with sputtering (as most sputter) that a regular breaker will never trip. This is simply untrue.

The number 42 is, in The Hitchhiker's Guide to the Galaxy by Douglas Adams, " Answer to the Ultimate Question of Life, the Universe, and Everything", calculated by an enormous supercomputer named Deep Thought over a period of 7.5 million years. Unfortunately, no one knows what the question is.

https://en.wikipedia.org/wiki/42_(number)
 

mbrooke

Batteries Included
Location
United States
Occupation
Technician
The number 42 is, in The Hitchhiker's Guide to the Galaxy by Douglas Adams, " Answer to the Ultimate Question of Life, the Universe, and Everything", calculated by an enormous supercomputer named Deep Thought over a period of 7.5 million years. Unfortunately, no one knows what the question is.

https://en.wikipedia.org/wiki/42_(number)



Which fits one theory I have, no one knows at what point incident energy at a fault equates to fire. In theory if I have a flammable atmosphere or something soaked in gasoline, 8 half cycles can still start a fire.
 

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
Well, I think that despite the flaws in his reasoning (and spelling*) behind what takes place, it is still a decent demonstration of the benefits. Sure, a "regular" breaker might have tripped, but we all know, it might not have. It also would not have tripped AS FAST as the AFCI if it was an arcing fault. In an arcing fault, faster clearing is always better despite the uncertainty of just how long it takes for the energy to be incendiary.

* Spelling chuckle: "Ampsity" instead of ampacity
 

mbrooke

Batteries Included
Location
United States
Occupation
Technician
Well, I think that despite the flaws in his reasoning (and spelling*) behind what takes place, it is still a decent demonstration of the benefits. Sure, a "regular" breaker might have tripped, but we all know, it might not have.

And what what those conditions be?



It also would not have tripped AS FAST as the AFCI if it was an arcing fault. In an arcing fault, faster clearing is always better despite the uncertainty of just how long it takes for the energy to be incendiary.

* Spelling chuckle: "Ampsity" instead of ampacity


What is an arcing fault? By definition 98% of short circuits are an arcing fault.
 

JFletcher

Senior Member
Location
Williamsburg, VA
Well, I think that despite the flaws in his reasoning (and spelling*) behind what takes place, it is still a decent demonstration of the benefits. Sure, a "regular" breaker might have tripped, but we all know, it might not have. It also would not have tripped AS FAST as the AFCI if it was an arcing fault. In an arcing fault, faster clearing is always better despite the uncertainty of just how long it takes for the energy to be incendiary.

* Spelling chuckle: "Ampsity" instead of ampacity

Pronouncing it that way as well.

Also, where can I get a copy of the 2009 NEC?

Because the AFCI was out of frame, we dont know if it or the breaker is what actually tripped. If the AFCI tripped, I'm gonna guess he shorted H->G; Ive seen several other videos showing AFCI breakers not tripping with arcs that go H->N.
 

romex jockey

Senior Member
Location
Vermont
Occupation
electrician
Which fits one theory I have, no one knows at what point incident energy at a fault equates to fire. In theory if I have a flammable atmosphere or something soaked in gasoline, 8 half cycles can still start a fire.


One would think the insurance cabal would have archived studies back to when man discovered fire by now Mr MBrooke.

Unfortunately, your Dumb & Dumber vid on afci installation may end up on their cutting room floor....

I watched until he cut thru the zip cord multiple times , and hadda shut it off

If this is our trades perception , we're doomed.

~RJ~
 

mbrooke

Batteries Included
Location
United States
Occupation
Technician
One would think the insurance cabal would have archived studies back to when man discovered fire by now Mr MBrooke.

Unfortunately, your Dumb & Dumber vid on afci installation may end up on their cutting room floor....

I watched until he cut thru the zip cord multiple times , and hadda shut it off

If this is our trades perception , we're doomed.

~RJ~


Its what they play off of. And being that this video is targeted toward DIYs his world is gold.
 

mbrooke

Batteries Included
Location
United States
Occupation
Technician
I never watched the video, but lemme guess:

This is another AFCI bashing thread.

Am I right? Did I win a prize.



Partly, but also to discuss what level of incident energy does it really take to ignite a fire and a standard breakers ability to mitigate it. In the vid the breaker did trip after the 4th try. To me I always assumed parallel arc faults would continue until ignition and not trip the breaker.
 

romex jockey

Senior Member
Location
Vermont
Occupation
electrician
Partly, but also to discuss what level of incident energy does it really take to ignite a fire and a standard breakers ability to mitigate it. In the vid the breaker did trip after the 4th try. To me I always assumed parallel arc faults would continue until ignition and not trip the breaker.

Mag Trip levels aren't as studied in the US , as elsewhere for residential protection.

The best it gets is explaining why the main OCPD tripped , and not the branch OCPD

Where this different, we'd have a much longer debate for you in this thread about the proper choices, as well as their incendiary expectations

That the Insurance industry has not delved into these specifics astounds me , given GC's will still be the major culprit if we installed AFD from 13.2KV all the way down to 120V circuitry


~RJ~
 

romex jockey

Senior Member
Location
Vermont
Occupation
electrician
I never watched the video, but lemme guess:

This is another AFCI bashing thread.

Am I right? Did I win a prize.

here ya go > :lol:

SiemensAFCI-1.jpg


~RJ~
 
Status
Not open for further replies.
Top